mqttinputdstream for mqttstreaming adapter
added mqtt adapter
added mqtt adapter library dependencies
added mqtt adapter wordcount example
add maven dependencies for mqtt
add maven dependencies for mqtt
remove unused dependency
remove unused dependency
modify code, use Spark Logging Class
Update MQTTInputDStream.scala
Update MQTTWordCount.scala
Split MapOutputTracker into Master/Worker classes.

Previously, MapOutputTracker contained fields and methods that
were only applicable to the master or worker instances.  This
commit introduces a MasterMapOutputTracker class to prevent
the master-specific methods from being accessed on workers.

I also renamed a few methods and made others protected/private.
Fix test failures in local mode due to updateEpoch
Unwrap a long line that actually fits.
Show "GETTING_RESULTS" state in UI.

This commit adds a set of calls using the SparkListener interface
that indicate when a task is remotely fetching results, so that
we can display this (potentially time-consuming) phase of execution
to users through the UI.
Update MQTTWordCount.scala
Update MQTTWordCount.scala
Add classmethod to SparkContext to set system properties.

Add a new classmethod to SparkContext to set system properties like is
possible in Scala/Java. Unlike the Java/Scala implementations, there's
no access to System until the JVM bridge is created. Since
SparkContext handles that, move the initialization of the JVM
connection to a separate classmethod that can safely be called
repeatedly as long as the same instance (or no instance) is provided.
Docs: Fix links to RDD API documentation
Shorten GETTING_RESULT to GET_RESULT